A subscriber identity module or subscriber identification module (SIM) is an integrated circuit that securely stores the international mobile subscriber identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). Some telephony devices, such as mobile phones, can include multiple SIMs in a single device.
Peripheral devices (e.g., cars, headsets, etc.) may be used to interact with mobile phones through a wireless communication protocol, such as Bluetooth™, to initiate phone calls using the mobile phones. For instance, a Bluetooth™ peripheral supporting the “Hands-free Profile” can initiate a phone call through a coupled mobile phone by sending a dial string that includes a phone number to the mobile phone. If the mobile phone includes more than one SIM, the mobile phone has to select one of the SIMs to use to place the phone call. For example, a user might have a first SIM used for his/her work calls and a second SIM used for his/her personal calls. In some situations, the mobile phone may use the incorrect SIM to place a phone call.